Schmolck et al (2002)

• The aim of the study was to investigate the effects of specific brain damage on semantic memory using case studies of brain damaged individuals compared to a control group.
• The control group had eight non brain damaged participants that were all matched for age, sex and education.
• The experimental group had six amnesia patients that were split into groups dependent on the level of brain damage.
• Two of the amnesia patients had a damaged hippocampus
• Three amnesia patients had encephalitis with medial temporal lobe and anterolateral temporal cortex damage
• Encephalitis is inflammation of the brain that can cause brain damage (like Clive Wearing)
• Nine tests were conducted over session with paticipants
• Seven tests were from the sematic battery test and two were conducted by the researchers.
• The tests used in the study were based on 24 animal and 24 object drawings. The 48 line drawings were categorized into eight groups.
• The tests were designed to measure semantic knowledge related to identifying, sorting or defining the line drawings. A further four tests were conducted on some of the patients and control participants.
• Tasks one to four were pointing to or naming a picture.
• Task five was based on semantic features of objects and participants had to answer yes/no questions on the physical and associated features of an object.
• Inter-rater reliability was established for scoring the accuracy ratings of the responses.
• Patients with a damaged hippocampus were able to point out objects and answer questions about objects with accuracy.
• Patients with damage to the medial temporal lobe performed less well at pointing, naming and answering questions about objects.
• All participants were ranked in terms of performance and the rank appeared to correspond directly with the extent of the brain damage.
• Damage to the anterolateral temporal cortex seemed to cause an impairment to semantic knowledge.
• Schmolck concluded that damage to the anterolateral temporal cortex is consistent with a loss of semantic knowledge resulting in a overlap of conceptual knowledge causing confusion.
• Schmolck concluded that semantic knowledge is associated with the anterolateral temporal cortex and not the medial temporal lobe.
• Semantic dementia patients impairment is restricted to the anterolateral temporal cortex and the medial temporal lobe is unaffected. MRI scans also suggest that the more progressed the disease is the greater the damage to the anterolateral temporal cortex.
• Evidence from semantic dementia support the findings that the anterolateral temporal cortex is involved in semantic memory
• Retrospective research cannot establish casual relationships between the injury and resulting impairments.
• The findings may reflect the ability of the brain to adapt to injury rather that the effect of the injury itself.
• Line drawings may not use semantic memory as it is used in everyday life therefore the study lacks ecological validity and the findings cannot be generalized.